明挖公路隧道基坑支护结构分析与施工工艺改进
发布时间：2019-04-01 22:57
【摘要】：随着地铁明挖公路隧道及高层建筑的大规模兴起，我国出现了越来越多的基坑工程基坑工程涉及岩土和结构工程，大多情况下，又属于临时工程，基坑工程的安全性成为基坑设计者和施工者关注的重点针对地铁及高层建筑的深基坑，国内已积累了较为丰富的工程设计经验和相对成熟的结构计算方法，，并将之应用于明挖公路隧道基坑工程的设计然而，明挖公路隧道基坑深度大多在13米以下，较地铁及高层建筑基坑浅得多，仅依靠以往工程设计经验是偏保守的片面的本文围绕明挖公路隧道基坑工程的特点，对工程中常用的单排桩钢板桩以及连续墙等支护结构进行结构验算，分析其在不同基坑深度和不同地质工况下的支护结构的工作性能，以期丰富明挖公路隧道基坑工程设计经验有效改进其施工工艺 首先，研究了适用于公路隧道基坑工程支护结构设计与分析方法，包括支护结构的破坏模式支护结构的基本假定和计算方法，为基坑开挖过程数值模拟提供研究基础 其次，根据基坑工程支护结构的计算原理，建立支护杆系有限元模型，进行基坑开挖过程中支护结构的内力及位移计算，讨论地质条件横向支撑间距横向支撑道数放坡高度等对支护结构的影响规律，结合工程实际需要，对施工工艺进行改进以便缩短施工工期 最后，对明挖公路隧道开挖深度最大的泵房原支护方案即单排桩与多道水平横向支撑支护方案进行改进，提出一种新的支护方案——采用工厂预制的钢板桩与双拼工字钢作为斜向支撑的支护方案，施工速度快，机械化程度高，并还对其进行结构验算 通过研究发现：单排桩支护结构的稳定性受横向支撑的布置和桩的嵌固深度影响较为明显，连续墙支护结构稳定性受嵌固深度影响较为明显，但受横向支撑的间距变化相对较小；对此提出了典型的施工改进工艺泵房基坑支护改进方案中，结构内力值与原设计方案基本相同，开挖过程中水平位移较小，对基坑周围地表沉降及建筑物的影响小，由于取消了立柱，保证了足够的施工机械和主体结构人工钢筋绑扎作业空间，有利于缩短施工工期
[Abstract]:With the large-scale rise of subway open-cut highway tunnel and high-rise buildings, more and more foundation pit projects in China are involved in geotechnical and structural engineering, in most cases, they are also temporary works. The safety of foundation pit engineering has become the focus of foundation pit designers and builders for the deep foundation pit of subway and high-rise buildings, and has accumulated rich engineering design experience and relatively mature structural calculation methods in China. However, most of the excavation depth of open-cut highway tunnel is less than 13 meters, which is much shallower than that of subway and high-rise building foundation pit. Only relying on the previous engineering design experience is a conservative one-sided, this paper focuses on the characteristics of open-cut highway tunnel foundation pit engineering, carries on the structural checking calculation to the single-row pile steel plate pile and the continuous wall and other supporting structures commonly used in the project. The working performance of supporting structure under different depth of foundation pit and different geological conditions is analyzed in order to enrich the design experience of open-cut highway tunnel foundation pit and improve its construction technology first of all. This paper studies the design and analysis method of supporting structure suitable for highway tunnel foundation pit engineering, including the basic assumption and calculation method of supporting structure with failure mode, which provides the research foundation for numerical simulation of foundation pit excavation process. According to the calculation principle of supporting structure in foundation pit engineering, the finite element model of supporting rod system is established to calculate the internal force and displacement of supporting structure in the process of foundation pit excavation. This paper discusses the influence of the number of lateral bracing paths on the supporting structure in geological conditions. In combination with the practical needs of the engineering, the construction technology is improved in order to shorten the construction period. The original supporting scheme of pump house with the largest excavation depth of open-cut highway tunnel is improved, that is, single row pile and multi-track horizontal lateral supporting scheme. A new supporting scheme is put forward, which adopts prefabricated steel sheet pile and double-jointed I-shaped steel in factory as inclined bracing scheme, which has the advantages of fast construction speed and high mechanization degree. It is also found that the stability of single row pile supporting structure is affected by the arrangement of lateral bracing and the depth of pile fixation, and the stability of continuous wall retaining structure is influenced by the embedded depth of retaining structure, and the stability of single row pile retaining structure is influenced by the depth of embedding. However, the spacing of the lateral brace is relatively small. In this paper, a typical improvement scheme for foundation pit support of pump house is put forward. The internal force of the structure is basically the same as that of the original design, and the horizontal displacement is small in the excavation process, and the influence on the settlement of the ground around the foundation pit and the building is small. Because the post is cancelled, enough construction machinery and main structure artificial reinforcement binding working space is guaranteed, which is helpful to shorten the construction period.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4;U452.11
本文编号：2451985
[Abstract]:With the large-scale rise of subway open-cut highway tunnel and high-rise buildings, more and more foundation pit projects in China are involved in geotechnical and structural engineering, in most cases, they are also temporary works. The safety of foundation pit engineering has become the focus of foundation pit designers and builders for the deep foundation pit of subway and high-rise buildings, and has accumulated rich engineering design experience and relatively mature structural calculation methods in China. However, most of the excavation depth of open-cut highway tunnel is less than 13 meters, which is much shallower than that of subway and high-rise building foundation pit. Only relying on the previous engineering design experience is a conservative one-sided, this paper focuses on the characteristics of open-cut highway tunnel foundation pit engineering, carries on the structural checking calculation to the single-row pile steel plate pile and the continuous wall and other supporting structures commonly used in the project. The working performance of supporting structure under different depth of foundation pit and different geological conditions is analyzed in order to enrich the design experience of open-cut highway tunnel foundation pit and improve its construction technology first of all. This paper studies the design and analysis method of supporting structure suitable for highway tunnel foundation pit engineering, including the basic assumption and calculation method of supporting structure with failure mode, which provides the research foundation for numerical simulation of foundation pit excavation process. According to the calculation principle of supporting structure in foundation pit engineering, the finite element model of supporting rod system is established to calculate the internal force and displacement of supporting structure in the process of foundation pit excavation. This paper discusses the influence of the number of lateral bracing paths on the supporting structure in geological conditions. In combination with the practical needs of the engineering, the construction technology is improved in order to shorten the construction period. The original supporting scheme of pump house with the largest excavation depth of open-cut highway tunnel is improved, that is, single row pile and multi-track horizontal lateral supporting scheme. A new supporting scheme is put forward, which adopts prefabricated steel sheet pile and double-jointed I-shaped steel in factory as inclined bracing scheme, which has the advantages of fast construction speed and high mechanization degree. It is also found that the stability of single row pile supporting structure is affected by the arrangement of lateral bracing and the depth of pile fixation, and the stability of continuous wall retaining structure is influenced by the embedded depth of retaining structure, and the stability of single row pile retaining structure is influenced by the depth of embedding. However, the spacing of the lateral brace is relatively small. In this paper, a typical improvement scheme for foundation pit support of pump house is put forward. The internal force of the structure is basically the same as that of the original design, and the horizontal displacement is small in the excavation process, and the influence on the settlement of the ground around the foundation pit and the building is small. Because the post is cancelled, enough construction machinery and main structure artificial reinforcement binding working space is guaranteed, which is helpful to shorten the construction period.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.4;U452.11
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